#include <iostream>
using namespace std;

void fun(int a, int b){
    cout<<"全局Sum:"<<a+b<<endl;
}
namespace A
{
    void fun(int a, int b){
        cout<<"SumA:"<<a+b<<endl;
    }
}
namespace B
{
    void fun(int a, int b){
        cout<<"SumB:"<<a+b<<endl;
    }
}namespace C
{
    void fun(int a, int b){
        cout<<"SumC:"<<a+b<<endl;
    }
}
int main(int argc, char const *argv[])
{
    int a = 6;
    int b = 7;
    int c = 8;
    A::fun(a,b);
    B::fun(b,c);
    C::fun(a,c);
    fun(a,b);

    return 0;
}
